Calculo de momento torsor en acero
Structural Engineering Report No. 276
Combined Bending and Torsion of Steel I-Shaped Beams
by Bruce G. Estabrooks and Gilbert Y. Grondin
January, 2008
Combined Bending and Torsion of Steel I-Shaped Beams
by Bruce E. Estabrooks and Gilbert Y. Grondin
Structural Engineering Report 276
Department of Civil &Environmental Engineering University of Alberta Edmonton, Alberta
January, 2008
Abstract Tests were conducted on six simply supported wide flange beams of Class 1 and 2 sections. The primary experimental variables included class of section, bending moment to torque ratio, and the inclusion or omission of a central brace. The end restraint and loading conditions were designed to simulatesimply supported conditions at both end supports and a concentrated force and moment at midspan. Initial bending moment to torque ratio varied from 5:1 to 20:1.
A finite element model was developed using the finite element software ABAQUS. Although the initial linear response was predicted accurately by the finite element analysis, the ultimate capacity was underestimates.
A comparison of thetest results with the design approach proposed by Driver and Kennedy (1989) indicated that this approach is potentially non-conservative and should not be used for ultimate limit state design. A design approach proposed by Pi and Trahair (1993) was found to be a suitable approach for ultimate limit states design.
Acknowledgements
This research project was funded by the Steel StructuresEducation Foundation and the National Research Council of Canada.
The test program was conducted in the I.F. Morrison Laboratory at the University of Alberta. The great efforts that Mr. Richard Helfrich has put in the design and erection of the test frame were invaluable to the success of the test program.
Feedbacks and comments provided by Dr. Robert Driver of the University of Alberta at theearly stage of this project are acknowledged with thanks.
Table of Contents
1. Introduction.................................................................................................... 1.1 1.2 General............................................................................................... Objectives and Scope.........................................................................1 1 1
2.
Literature Review........................................................................................... 2.1 2.2 2.3 2.4 2.5 General............................................................................................... Elastic Torsion Theory....................................................................... Steel Beams Subjected to Torsion Only............................................ Elastic Design Methods for Combined Bending and Torsion ........... Inelastic Design Methods for Combined Bending and Torsion.........
2 2 2 4 5 8
3.
Experimental Program ................................................................................... 3.1 3.2 3.3 Test Program Objectives.................................................................... MaterialTests..................................................................................... Test Set-Up and Procedure ................................................................ 3.3.1 3.3.2 3.3.3 3.4 End Conditions....................................................................... Loading of the Test Specimens.............................................. Lateral BracingSystem..........................................................
15 15 15 16 16 18 19 21
Instrumentation and Data Acquisition ...............................................
4.
Experimental Results ..................................................................................... 4.1 4.2 4.3 4.4 General..................................................................................................
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